How’d Griffin do it? By including rechargeable lithium-ion batteries in the speakers themselves. Once they’re fully charged (just sit them on the base station’s cradle), Griffin says they can be placed anywhere within 150 feet. And because they communicate via RF, walls and obstructions shouldn’t pose a problem–adjoining rooms and nearby outdoor spaces (patios, decks) are fair game. Griffin says the fully charged speakers should deliver 10 hours of playing time before needing another juice-up. And the detached speakers aren’t limited to what your iPod can play; the base station’s line-in cradle accepts a stereo input from virtually any source. (Yes, the base station still needs a power cord–but that’s the only wire that the system should require if you’re listening to your iPod.)